Carbamylbiuret-modified polyisocyanates

ABSTRACT

A carbamylbiuret-modified polyisocyanate of the formula: ##STR1## wherein n is an integer of from about 1 to about 20; R is a divalent radical containing from about 1 to about 18 carbon atoms; and Y is a divalent radical selected from the group consisting of: ##STR2## wherein D is selected from the group consisting of O, S, and NH; X, X&#39;, and X&#34; are independently selected from the group consisting of oxygen and sulfur; R 2  and R 3  are independently selected from the group consisting of aryl of from about 6 to about 18 carbon atoms, alkyl containing from about 1 to about 6 carbon atoms, and cycloalkyl containing from about 3 to about 7 carbon atoms, provided that each of R 2  and R 3  differs from R; and R 4 , R 5 , R 6 , and R 7  are independently selected from the group consisting of hydrogen, alkyl containing from about 1 to about 6 carbon atoms, cycloalkyl containing from about 3 to about 7 carbon atoms, phenyl, and benzyl. The compounds of the invention are useful for preparing urethane based microcellular foams and elastomers.

This is a continuation-in-part of application Ser. No. 92,479, filedNov. 8, 1979, now U.S. Pat. No. 4,271,087.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to novel, carbamylbiuret-modified polyisocyanateswhich are useful for preparing urethane-based microcellular foams andelastomers having excellent physical properties.

2. Description of the Prior Art

Urethane-based microcellular foams and elastomers are widely used inindustry. Thus, these foams and elastomers are used to prepare exteriorautomobile parts, coatings, and adhesives.

Many biuret polyisocyanates are known to those skilled in the art. Thesebiuret polyisocyanates may be prepared by reacting an organicdiisocyanate with water (U.S. Pat. Nos. 3,124,605 and 3,903,127), formicacid (U.S. Pat. No. 3,350,438), tertiary alcohols (U.S. Pat. No.3,358,010), monoamines (U.S. Pat. No. 3,392,183), diamines (U.S. Pat.Nos. 3,441,588 and 3,903,126), ureas (U.S. Pat. No. 3,367,956 and U.K.Pat. No. 1,043,674), and other biuretizing agents (U.S. Pat. No.3,903,127).

Biuret polyisocyanates react with compounds bearing active hydrogen toform polyurethanes; see, e.g., U.S. Pat. No. 3,201,372.

German Pat. No. 883,504 discloses a reaction between ureas andisocyanates to prepare a reaction mixture having a high isocyanatecontent. According to U.S. Pat. No. 3,367,956, the process of the GermanPatent results only in a high molecular weight condensation product.

Ureas are disclosed to react with diisocyanates by Angewandte Chemie 72(1960), page 1002.

U.S. Pat. No. 3,367,956 discloses a process for the preparation ofbiuret polyisocyanates wherein an organic polyisocyanate is reacted witha substituted urea at a temperature of from about 150 to about 250degrees Centigrade. It is believed that the process of this patentproceeds in accordance with the following reaction: ##STR3##

German Offen. No. 2,329,300 discloses a process for the preparation ofiminoimidazolidinedions-modified polyisocyanate wherein diisocyanate isreacted with hydrocyanic acid and an organic tertiary amine catalyst.

U.S. Pat. No. 3,775,427 discloses a process for the preparation ofpolyisocyanates which contain hydantoin groups wherein a polyisocyanateis reacted with a α,ω-bis-(hydantoinyl)alkane. The products of thispatent are either viscous liquids or solids. They are unsuitable for usein urethane elastomeric microcellular foams for several reasons. In thefirst place, their structure contains a relatively long, flexible alkyl(or other type) bridge connecting the two hydantoin rings, therebycausing a less effective phase separation of hard and soft segments inthe resulting final product and resulting in an impairment of thephysical properties of the elastomer made from this product. In thesecond place, the physical states of these compounds and their low --NCOcontents render their use in microcellular systems impractical.

SUMMARY OF THE INVENTION

This invention provides novel carbamylbiuret-modified polyisocyanatesand polyurethane derived therefrom.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with this invention, there is provided acarbamylbiuret-modified polyisocyanate of the formula: ##STR4## whereinn is an integer of from about 1 to about 20; R is a divalent radicalcontaining from about 1 to about 18 carbon atoms; and Y is a divalentradical selected from the group consisting of: ##STR5## wherein D isselected from the group consisting of O, S, and NH; X, X', and X" areindependently selected from the group consisting of oxygen and sulfur;R² and R³ are independently selected from the group consisting of arylof from about 6 to about 18 carbon atoms, alkyl containing from about 1to about 6 carbon atoms, and cycloalkyl containing from about 3 to about7 carbon atoms, provided that each of R² and R³ differs from R; and R⁴,R⁵, R⁶, and R⁷ are independently selected from the group consisting ofhydrogen, alkyl containing from about 1 to about 6 carbon atoms,cycloalkyl containing from about 3 to about 7 carbon atoms, and aryl offrom about 6 to 18 carbon atoms.

The carbamylbiuret-modified polyisocyanates of this invention may berepresented by the formula: ##STR6## wherein n, R, and Y are ashereinbefore described.

It is preferred that n be from about 1 to about 20. In a more preferredembodiment, n is from about 1 to about 10.

R is an organic radical obtained by removing the --NCO groups from theorganic diisocyanate used to make the carbamylbiuret-modifiedpolyisocyanate of this invention. It is preferred that R contain fromabout 1 to about 18 carbon atoms. In a more preferred embodiment, R isan aromatic radical containing from about 6 to about 15 carbon atoms.

In one preferred embodiment, the carbamylbiuret-modified polyisocyanateof this invention contains carbodiimide linkages of the formula:

    --N═C═N--.

This carbodiimide-carbamylbiuret-modified polyisocyanate is prepared byreacting a carbodiimide-modified organic isocyanate with a urea-typecompound. The carbodiimide-containing species in saidcarbodiimide-carbamylbiuret-modified polyisocyanate represent from about2 to about 50 percent of the weight of the polyisocyanate. It ispreferred that said polyisocyanate contain from about 5 to about 30percent (by weight) of these carbodiimide species; it is even morepreferred that the polyisocyanate contain from about 8 to about 20percent (by weight) of carbodiimide species.

Any suitable carbodiimide-modified organic polyisocyanate may be used toprepare the carbodiimide-carbamylbiuret-modified polyisocyanate of thisinvention. These carbodiimide-modified organic polyisocyanates are wellknown to those skilled in the art. They may be prepared, e.g., by theprocedures described in U.S. Pat. No. 3,152,162, in German Pat. No.1,092,007, in an article by T. W. Campbell and K. C. Smeltz appearing inJ. Org. Chem., 28, 2069 (1963), and in an article by D. J. Lyman and N.Sadri appearing in Makromel. Chem., 67, 1 (1963).

One means of preparing the carbodiimide-modified polyisocyanates used inthe process of this invention is to heat the organic diisocyanates knownto the art. Extended heating of isocyanates results in the condensationof the isocyanate to a carbodiimide with elimination of carbon dioxidein accordance with the following equation: ##STR7##

Certain phospholenes and phospholene oxides catalyze the transformationof isocyanates to carbodiimide linkages, e.g.,1-ethyl-3-methyl-3-phospholene oxide, 1-phenyl-3-methyl-3-phospholeneoxide. Also, simple trialkyl phosphine oxides, and the like may be usedto catalyze the reaction.

The carbodiimide-modified polyisocyanates which are used to prepare thecarbodiimide-carbamylbiuret-modified polyisocyanates of this inventionhave NCO contents of from about 20 to about 31 percent and contain fromabout 5 to about 50 percent (by weight) of carbodiimide-containingspecies. It is preferred that said carbodiimide-modified polyisocyanateshave NCO contents of from about 26 to about 30 percent and contain fromabout 10 to about 35 percent (by weight) of carbodiimide-species. In themost preferred embodiment, the carbodiimide-modified polyisocyanateshave NCO contents of from about 28 to about 30 percent and contain fromabout 15 to about 25 percent (by weight) of carbodiimide-species.

In one preferred embodiment, the carbodiimide-modified polyisocyanate isprepared by heating to a temperature of from about 150 to about 300degrees Centigrade a polyisocyanate of the diphenyl methane series untila maximum of 33 percent of the existing isocyanate groups have reactedto form the carbodiimide. This carbodiimide-modified polyisocyanate isprepared in accordance with the procedure of U.S. Pat. No. 3,152,162.One of its most preferred embodiments absorbs light in the infraredrange of from 5.76 to 5.78 microns and from 7.22 to 7.24 microns.

In another preferred embodiment, R is ##STR8## where R⁸ is methyl and aand b are integers of from 0 to 2. In this embodiment it is preferredthat R be ##STR9##

It is preferred that the carbamylbiuret-modified polyisocyanate of thisinvention have an NCO content of from about 20 to about 32 percent. Itis more preferred that the NCO content of this polyisocyanate be fromabout 22 to about 31 percent.

Y is a divalent radical derived from the urea-type compounds which areused to prepare the polyisocyanates of this invention. In general, Y isobtained by removing hydrogen atoms from the nitrogen atoms in theurea-type compound.

The preferred urea-type compounds which may be used to prepare thecompositions of this invention are described by the formulae: ##STR10##wherein R², R³, R⁴, R⁵, R⁶, R⁷, X, X', and X" are as hereinbeforedescribed. By way of illustration and not limitation, some of thepreferred ureas which may be used to prepare the compositions of thisinvention include N,N'-dimethylurea, N,N'-dimethylthiourea,N,N'-diethylurea, N,N'-diethylthiourea, N,N'-di-n-propylurea,N,N'-di-n-propylthiourea, N,N'-di-t-butylurea, N,N'-di-t-butylthiourea,N,N'-dicyclohexylurea, N,N'-dicyclohexylthiourea, N,N'-diphenylurea,N,N'-diphenylthiourea, N-methyl-N'-benzylurea,N-methyl-N'-benzylthiourea, ethyleneurea, ethylenethiourea,propyleneurea, propylenethiourea, n-butyleneurea, n-butylenethiourea,hydantoin, 5-methylhydantoin, 5-ethylhydantoin, 5-n-propylhydantoin,5-t-butylhydantoin, 5-nitrohydantoin, 5-sec-butylhydantoin,5-phenylhydantoin, 2-thiohydantoin, 4-thiohydantoin,2,4-dithiohydantoin, 5,5-dimethylhydantoin, 5,5-diethylhydantoin,5,5-di-n-propylhydantoin, 5,5-diphenylhydantoin,5-methyl-5-ethylhydantoin, 5-methyl-5-isopropylhydantoin,5,5-diphenyl-2-thiohydantoin, 1,3-diphenylguanidine, allantoin,barbituric acid, parabanic acid, cyanuric acid, uracil, and the like.

Any suitable organic isocyanate may be used in the process of thisinvention. One may use isocyanates which contain substantially nocarbodiimide linkages in said process; when this is done, one obtainscarbamylbiuret-modified polyisocyanates. Alternatively, one may convertan isocyanate to carbodiimide linkages by heat or catalyst and thenreact the product obtained with the urea-type compounds; when this isdone, one obtains carbodiimide-carbamylbiuret-modified polyisocyanates.Thus, some of the isocyanates which may be used in this process include,for example, aromatic isocyanates such as,1-methylbenzene-2,4-diisocyanate, 1-methylbenzene-2,6-diisocyanate,1-methoxybenzene-2,4-diisocyanate, 1-chlorobenzene-2,4-diisocyanate,1-benzylbenzene-2,6-diisocyanate, 2,6-diethylbenzene-1,4-diisocyanate,diisopropylbenzene diisocyanates, triisopropylbenzene diisocyanates,1,3-dimethoxybenzene-2,4-diisocyanate, 1-nitrobenzene-2,4-diisocyanate,technical mixtures of 2,4- and 2,6-toluene diisocyanates, m- andp-phenylene diisocyanates, m-xylylene diisocyanate, p-xylylenediisocyanate, naphthylene-1,5-diisocyanate,diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,2'-diisocyanate,diphenylmethane-4,2'-diisocyanate,3,3'-dimethoxydiphenylmethane-4,4'-diisocyanate,dimethyldiphenylmethane-4,4'-diisocyanate,3-methyldiphenylmethane-4,4'-diisocyanate, 1-(isocyanatophenyl)-ethylisocyanate, 4,4'-biphenyl diisocyanate, 4,4'-diphenyl sulphonediisocyanate, aromatic diisocyanates which have been substituted byvarious substituents such as alkoxy-, nitro, chloro, or bromo-,chlorophenylene-2,4-diisocyanate, and the like. Thus, one may usealiphatic, cycloaliphatic, and araliphatic isocyanates such as,tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylenediisocyanate, 1,3-cyclopentylene diisocyanate, 1,4-cyclohexylenediisocyanate, 1,2-cyclohexylene diisocyanate, hexahydroxylylenediisocyanate, 4,4'-dicyclohexyl diisocyanate,1,2-di-(isocyanatomethyl)-cyclobutane,1,3-bis(isocyanatopropoxy)-2,2-dimethyl propane,1,3-bis-(isocyanato-propyl)-2-methyl-2-propylpropane,1-methyl-2,4-diisocyanatocyclohexane,1-methyl-2,6-diisocyanatocyclohexane,bis-(4-isocyanatocyclohexyl)-methane, 1,4-diisocyanatocyclohexane,1,3-diisocyanatocyclohexane, isophorone diisocyanate,2,6-diisocyanatocaproic acid ester, an isomeric mixture of1-methyl-2,4-diisocyanatocyclohexane and1-methyl-2,6-diisocyanatocyclohexane, 3,3,5-trimethyl-5-isocyanatomethylcyclohexylisocyanate, methyl-substituted hexamethylene-and pentamethylene-diisocyanate, and the like. Other organic isocyanateswell known to those in the art may also be used such as, mixtures of2,2'-, 2,4'-, and 4,4'-diphenylmethane diisocyanates,polyphenylpolymethylenepolyisocyanates, mixtures of diphenylmethanediisocyanates and polyphenylpolymethylenepolyisocyanates, mixtures of4,4'-diphenylmethane diisocyanates and 2,4- and 2,6-toluenediisocyanates, crude isocyanates from the phosgenation of toluenediamine, and the like.

It is preferred to use a diisocyanate selected from the group consistingof toluene diisocyanate, hexamethylene diisocyanate, diphenylmethanediisocyanate, and the dimethyl derivative of diphenylmethanediisocyanate. The most preferred diisocyanate is diphenylmethanediisocyanate.

The compositions of this invention may be prepared by reacting anisocyanate of the formula OCNRNCO (reactant I) with a urea-type compoundof the formula HYH (reactant II). From about 2 to about 50 moles ofreactant I are used for each mole of reactant II. It is preferred to usea reactant I/reactant II mole ratio of from about 3 to about 25; in themost preferred embodiment, said mole ratio is from about 5 to about 20.

In the process of this invention, reactants I and II are heated togetherat a temperature of from about 60 to about 250 degrees Centigrade forfrom about 0.2 to about 20 hours until the NCO content of the reactionmixture is from about 20 to about 32 percent. It is preferred to heatreactants I and II at a temperature of from about 80 to about 250degrees Centigrade for from about 0.2 to about 15 hours until the NCOcontent of the reaction mixture is from about 22 to about 31 percent. Inthe most preferred embodiment, the reactants are heated at a temperatureof from about 80 to about 230 degrees Centigrade for from about 0.2 toabout 10 hours until the NCO content of the reaction mixture is fromabout 22 to about 30 percent.

It is preferred to use nitrogen as a blanketing gas in the process ofthis invention.

The reaction between reactants I and II may be carried out with orwithout a solvent. If a solvent is used, it is preferred that it notcontain any hydrogen atoms which would react with --NCO groups. Suitablesolvents include ethyl acetate; ketones, glycolmethyl ether acetate;chlorinated aliphatic, hydroaromatic, or aromatic hydrocarbons such asmethylene chloride, perchlorocyclohexane, orthodichlorobenzene; and thelike.

The polyisocyanates of this invention may be used to prepare cellularpolyurethanes by reacting them with an active hydrogen-containingcompound in the presence of a blowing agent. A suitable apparatus andprocess which may be used to prepare cellular polyurethane plastics aredescribed in U.S. Pat. No. Re. 24,514.

Water may be added as the blowing agent. When water is used,corresponding quantities of excess isocyanate which react with the waterand produce carbon dioxide may be used.

One may also prepare the polyurethane plastics of this invention by aprepolymer technique wherein an excess of organic polyisocyanate isreacted in a first step with a polyol to prepare a prepolymer havingfree --NCO groups and the prepolymer is reacted in a second step withpolyol and a blowing agent to prepare a foam. When this is done, wateror low-boiling hydrocarbons may be used as the blowing agents. Somehydrocarbons which are suitable for this purpose include pentane;hexane; heptane; pentene; heptene; halogenated hydrocarbons such as,dichlorodifluoroethane, dichlorodifluoromethane, trichlorofluoromethane,vinylidene chloride, methylene chloride, mixtures of the aforementioned,and the like; azo compounds such as azohexahydrobenzodinitrile; andother blowing agents well known in the art.

Alternatively, one may react the polyisocyanate of this invention andthe active hydrogen-containing compound in a single step. When this isdone, it is preferred that one use a suitable catalyst such as, stannouschloride, a stannous salt of a carboxylic acid having from about 1 to 18carbon atoms, a trialkyl tin oxide, a dialkyl tin chloride, a dialkyltin oxide or a dialkyl tin salt of a carboxylic acid having from about 1to about 18 carbon atoms, and other catalysts well known to thoseskilled in the art for this purpose. The aforementioned catalysts may beused by themselves or in combination with another suitable catalyticcompound such as, a tertiary amine (such as triethylenediamine);N,N,N',N'-tetramethyl butanediamine; a 1-alkyl-4(dialkylaminoalkyl)piperazine in which the alkyl radicals of the dialkylamino group containfrom about 1 to about 4 carbon atoms and the alkyl radical bearing thedialkylamino group contains from about 2 to about 4 carbon atoms;N-ethylmorpholine; the catalysts disclosed in U.S. Pat. Nos. 2,948,928,2,941,967, 2,948,691; and other catalysts well known to those in theart.

The polyisocyanate of this invention is reacted with an organic compoundwhich contains active hydrogen-containing groups. By way of illustrationand not limitation, some of the active hydrogen-containing compoundswhich may be used in the process of this invention include polyesterpolyols, polyether polyols, polythioether polyols, polyacetals polyols,and the like.

Any suitable organic compound which contains at least two activehydrogen-containing groups (as determined by the Zerewitinoff method)may be used in the process of this invention.

In one preferred embodiment, said organic compound contains a pluralityof active hydrogen-containing groups and at least some alcoholichydroxyl groups. The hydroxyl groups react with --NCO groups to yieldurethane groups. The alcoholic group is preferred because it is readilyavailable and yields a stronger urethane linkage than a phenolic typehydroxyl group.

The organic compound which contains at least two activehydrogen-containing groups may contain, --OH, --NH₂, --NH, --COOH, and--SH groups. Some examples of this type of organic compound include,polyhydroxyl polyesters; polyhydric polyalkylene ethers; polyhydricpolythioethers; polyacetal polyols; aliphatic polyols such as, alkane,alkene, and alkyne diols, triols, tetrols, and the like; aliphaticthiols including alkane, alkene, and alkyne thiols having two or more--SH groups; polyamines including both aromatic, aliphatic, andheterocyclic diamines, triamines, tetramines, and the like. Compoundswhich contain two or more active hydrogen-containing groups also may beused in the process of this invention; thus, one may use amino alcoholswhich contain two amino groups and one hydroxyl group, compounds whichcontain one --SH group and one --OH group, compounds which contain two--OH groups and one --SH group, compounds which contain an amino groupand an --SH group, and the like.

The molecular weight of the organic compound containing the activehydrogen-containing groups may vary over a wide range. It is preferredthat at least one of the active hydrogen-containing compounds have amolecular weight of at least about 200. It is more preferred that saidcompound have a molecular weight of from about 500 to about 5000, ahydroxyl number of from about 25 to about 800, and an acid number (whereapplicable) of below about 5. It is preferred that the molecular weightof said compound not exceed about 10,000, but a higher molecular weightcan be used as long as satisfactory mixing of the activehydrogen-containing compound with the polyisocyanates of this inventioncan be obtained.

In one preferred embodiment, an organic compound containing activehydrogen groups with a molecular weight of from about 200 to about10,000 is used together with an organic compound with activehydrogen-containing groups which has a molecular weight of below about750. It is preferred that the molecular weight of this latter compoundbe below about 500. Aliphatic diols and triols are most preferred forthis purpose.

The active hydrogen-containing organic compound may be a polyhydroxylpolyester. Any suitable hydroxyl polyester may be used such as thoseobtained from polycarboxylic acids and polyhydric alcohols.

The active hydrogen-containing compound may be a polycarboxylic acid.Any suitable polycarboxylic acid may be used such as, oxalic acid,malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid,suberic acid, azelaic acid, brassylic acid, sebacic acid, thapsic acid,maleic acid, fumaric acid, glutaconic acid, alpha-hydromuconic acid,beta-hydromuconic acid, alpha-butyl-alpha-ethylglutaric acid, alpha,beta-diethylsuccinic acid, isophthalic acid, terephthalic acid,hemimellitic acid, trimellitic acid, trimesic acid, mellophanic acid,prehnitic acid, pyromellitic acid, benzenepentacarboxylic acid,1,4-cyclohexanedicarboxylic acid, 3,4,9,10-perylenetetracarboxylic acid,and the like.

The active hydrogen-containing compound may be a polyhydric alcohol suchas, ethylene glycol, propylene glycol, 1,3-propane diol, butyleneglycol, 1,4-butane diol, 1,3-butane diol, 1,5-pentane diol, 1,4-pentanediol, 1,3-pentane diol, 1,6-hexane diol, 1,7-heptane diol, glycerine,trimethylolpropane, 1,3,6-hexanetriol, triethanolamine, pentaerythritol,sorbitol, and the like.

The active hydrogen-containing compound may be a polyhydric polyalkyleneether. Some suitable polyhydric polyalkylene ethers include, forexample, the condensation product of an alkylene oxide wherein thecondensation is initiated with compounds known to the art. The initiatormay be a difunctional compound, such as water, so that the resultingpolyether is essentially a chain of repeating oxyalkylene groups as onefinds in polyethylene ether glycol, polypropylene ether glycol,polybutylene ether glycol, and the like. The initiator may be anysuitable active hydrogen-containing compound. It is preferred that theinitiator contain from about 2 to about 8 active sites to which thealkylene oxides may add. Alkylene oxides which may be used to preparethe polyhydric polyalkylene ether include ethylene oxide, propyleneoxide, butylene oxide, amylene oxide, epihalohydrins such as,epichlorohydrin, styrene oxide, and the like. Initiators which may beused include water, ethylene glycol, propylene glycol, glycerine,trimethylolpropane, pentaerythritol, sorbitol, sucrose, ammonia,diethanolamine, triethanolamine, dipropanolamine, tripropanolamine,2,4-tolylenediamine, 4,4'-diphenylmethanediamine, p, p',p"-triphenylmethanetriamine, ethylenediamine, propylenediamine,dipropylenetriamine, N,N,N',N'-tetrakis-(2-hydroxypropyl)ethylenediamine, diethylenetriamine, and the like.

The process for preparing polyhydric polyalkylene ethers is well knownto those in the art and is described in U.S. Pat. Nos. 1,922,459,3,009,939, and 3,061,625 and in the Encyclopedia of Chemical Technology,Volume 7, pages 257 to 262, published by Interscience Publishers, Inc.,in 1951.

The active hydrogen-containing compound may be a polyhydricpolythioether. Some of the polyhydric polythioethers which may be usedin the process of this invention include the condensation product ofthiodiglycol, the reaction product of a polyhydric alcohol with athioetherglycol, and the polyhydric polythioethers disclosed in U.S.Pat. Nos. 2,862,972 and 2,900,368.

A polyhydroxyl polyester which is also a polyester amide also may beused as the active hydrogen-containing compound. Thus, such compoundsmay be prepared by including some amine or amino alcohol in thereactants used for the preparation of the polyhydroxyl polyesters.Polyester amides may be obtained by condensing an amino alcohol (such asethanolamine) with the polycarboxylic acids described hereinabove; orthey may be made with the same components used for the polyhydroxylpolyester with a portion of the components being a diamine.

The active hydrogen-containing compound may be a polyacetal polyol. Somesuitable polyacetals include, the reaction product of an aldehyde (suchas formaldehyde) with a polyhydric alcohol.

In one preferred embodiment, the active hydrogen-containing compound isan aliphatic polyol. Some of the suitable aliphatic polyols which may beused include, alkanediols such as, ethylene glycol, trimethylene glycol,propylene glycol, tetramethylene glycol, 1,3-butanediol,1,5-pentanediol, 1,3-pentanediol, 1,6-hexanediol, 1,7-heptanediol,2,2-dimethyl-1,3-propanediol, 1,8-octanediol, 1,20-eicosanediol, and thelike; alkenediols such as, 2-pentene-1,5-diol, 2-hexene-1,6-diol,2-hexene-1,7-diol, and the like; alkyne diols such as,2-butyne-1,4-diol, and the like; alkanetriols such as,1,3,6-hexanetriol, 1,3,7-heptanetriol, 1,4,8-octanetriol,1,6,12-dodecanetriol, and the like; alkenetriols such as, alkynetriolssuch as 2-hexyne-1,3-6-triol and the like; alkanetetrols such as,1,2,5,6-hexanetetrol; alkenetetrols such as, 3-heptene-1,2,6,7-tetrol;alkynetetrols such as, 4-octyne-1,2,7,8-tetrol; and other aliphaticpolyols well known to those skilled in the art.

The active hydrogen-containing compound may be an aliphatic thiol whichcontains two or more --SH groups. Some suitable aliphatic thiolsinclude, 1,2-ethanedithiol, 1,3-propanedithiol, 1,2-propanedithiol,1,6-hexanedithiol, 1,3,6-hexanetrithiol, 2-butene-1,4-dithiol,3-hexyne-1,6-dithiol, and the like.

The active hydrogen-containing compound may be a polyamine. Somesuitable polyamines include, aromatic polyamines such as,p-aminoaniline, 1,5-diaminonaphthalene, 2,4-diaminotoluene,1,3,5-benzenetriamine, 1,2,3-benzenetriamine,1,4,5,8-naphthalenetetramine, and the like; aliphatic polyamines suchas, ethylenediamine, 1,3-propanediamine, 1,4-butanediamine,1,3-butanediamine, diethylenetriamine, triethylenetetramine,1,3,6-hexanetriamine; 1,3,5,7-heptanetetramine, and the like.

The following examples are presented to illustrate the claimed inventionand are not to be deemed limitative thereof. Unless otherwise stated,all parts are by weight, all percentages are by weight, and alltemperatures are in degrees Centigrade.

EXAMPLES 1-27

The specified amounts of diphenylmethane diisocyanate (MDI) and aurea-type compound were heated under nitrogen under the time andtemperature conditions described until the NCO content reached apredetermined level. In Examples 1-7 the urea-type compound was2-imidazolidone. In Examples 8-13 the urea-type compound was5,5-dimethylhydantoin. In Examples 14-15 the urea-type compound washydantoin. In Examples 16-18 the urea-type compound was1,3-dimethylurea. In Examples 19-22 the urea-type compound was5,5-diphenylhydantoin. In Example 23, 3,6-dihydroxy pyridazine was usedas the urea-type compound. 2-Imidazolidinethione and1,3-diphenylguanidine were used as the urea-type compounds in Examples24-25 and 26-27, respectively.

    ______________________________________                                                                    Reaction                                                                             Re-                                                          Urea-Type Temp-  action                                                       Compound, erature,                                                                             Time, %                                    Example                                                                              MDI, grams grams     °C.                                                                           hours NCO                                  ______________________________________                                        1      1930       170.0     120-150                                                                              3.0   22.4                                 2      1978       122.0     120-150                                                                              3.0   26.0                                 3      2044       56.0      120    1.0   30.4                                 4      2100       42.0      200    5.7   29.6                                 5      2100       58.0      200    0.5   28.5                                 6      2100       63.0      200    15.8  26.1                                 7      2100       130.0      55-200                                                                              0.6   25.7                                 8      1609       190.8     220    6.5   22.9                                 9      1663       136.8     220    5.3   26.1                                 10     1473       55.0      220    2.2   29.8                                 11     2100       78.4      220    4.2   29.2                                 12     2100       172.7     220    4.2   26.0                                 13     2100       268.9     230    0.7   26.0                                 14     2035       65.0      220    1.2   30.3                                 15     1403       97.5      220    2.2   23.7                                 16     1928       172.2     120    19.5  23.5                                 17     1976       123.9     120    13.0  26.2                                 18     2041       58.8      120    5.0   30.4                                 19     2100       52.5      230    9.0   25.7                                 20     2100       52.5      230    15.5  20.0                                 21     2100       119.7     230    1.2   30.1                                 22     2100       268.8     230    2.6   25.5                                 23     2100       52.5      200    1.7   30.7                                 24     2100       67.2      200    1.0   29.1                                 25     2100       147.0     200    2.0   24.0                                 26     2100       84.0      200    0.75  26.9                                 27     2100       63.0       67-200                                                                              0.7   28.9                                 ______________________________________                                    

EXAMPLE 28

In substantial accordance with the procedure described in Examples 1-27,600 grams of a pure diphenylmethane diisocyanate (isocyanate 1) werereacted with 36 grams of diethylurea at a temperature of 100 degreesCentigrade for 2.0 hours until the NCO content of the reaction mixturewas 29.2 percent. The product had a viscosity of 42 centipoises (at 25degrees Centigrade).

EXAMPLE 29

In substantial accordance with the procedure described for Examples1-27, 600 grams of isocyanate 1 were reacted with 36 grams ofdicyclohexylurea at a temperature of 120 degrees Centigrade for 3.0hours until the NCO content of the reaction mixture was 29.6 percent.The product had a viscosity of 42 centipoises (at 25 degreesCentigrade).

EXAMPLE 30

An isocyanate blend containing equal parts of an isocyanate derived fromlow molecular weight glycol and diphenylmethane diisocyanate (isocyanate2) and of the isocyanate of Example 3 was prepared by rolling theisocyanates for 1-2 hours. Three hundred point eight (300.8) parts ofthis isocyanate blend were weighed into a quart Plastikan, and 400 partsof a resin blend were added rapidly to the Plastikan. The resin blendcontained components in the ratio of 70 parts (by weight) of an ethyleneoxide capped polyol of oxypropylated propylene glycol with a molecularweight of 3500 (polyol 1), 30 parts (by weight) of a 6700 molecularweight triol (polyol 2), 23.5 parts (by weight) of 1,4-butanediol, 0.02parts (by weight) of dibutyltindilaurate, and 2.0 parts (by weight) of asolution containing a 1:3 mixture (by weight) of triethylene diamine and1,4-butanediol.

The mixture of the isocyanate blend and the resin blend were agitated inthe Plastikan with a high-speed drill fitted with a Cowles dissolver for10 seconds. The system blend was poured quickly into an all-aluminummold preheated to a temperature of 130-140 degrees Fahrenheit. After 4minutes, the resulting solid pad was pulled from the mold and post-curedin an oven for one hour at a temperature of 250 degrees Fahrenheit. Thesolid was then aged for from about 3 to 5 days at room temperature andthereafter evaluated.

Physical tests were performed in accordance with procedures well knownto those skilled in the art. The density determinations were made inaccordance with the procedure described in A.S.T.M. D-792. The tensilestrength, tensile modulus, and elongation determinations were made inaccordance with the procedure described in A.S.T.M. D-412. The splittear test is described in A.S.T.M. D-1938. The Shore D hardnessprocedure is described in A.S.T.M. D-2440. The flex modulus test wasconducted in accordance with A.S.T.M. D-790. The flex recovery test isdescribed in Materials Standard #CTZ 22003, Chevrolet Motor Standard,G.M.C. The heat sag determination was done in accordance with MaterialsStandard #CTZ 22006, Chevrolet Motor Division, G.M.C. The Dart impacttest is described in Fisher Body Specification FBMS 2-23. Each of thesepublications is hereby incorporated into this specification byreference.

The polyurethane foam of this Example had a density (pcf.) of 61.96; atensile-strength (p.s.i.) of 2010; a tensile modulus (p.s.i., 100%) of1665; an elongation (percent) of 220; a split tear (pounds per inch) of416; a Graves tear (Die C, pounds per inch) of 508; a Shore D hardnessof 55-50; a flex recovery of 14.5/7; a flex modulus (in thousands ofpounds per square inch) of 74.07, 26.5, and 10.91 at minus 20 degreesFahrenheit, 72 degrees Fahrenheit, and 150 degrees Fahrenheit,respectively; a heat sag (at 250 degrees Fahrenheit) of 0.28; and Dartimpact ratings of NF, NF, and F at 20 degrees Fahrenheit, 10 degreesFahrenheit, and 0 degrees Fahrenheit, respectively.

COMPARATIVE EXAMPLE 31

In substantial accordance with the procedure of Example 30, apolyurethane foam was prepared using an isocyanate blend containing 50parts of isocyanate 2 and 50 parts of a carbodiimide-modifiedpolyisocyanate (isocyanate 3), the carbamylbiuret-modifiedpolyisocyanate of this invention was not used in the experimentdescribed in this Example.

The polyurethane foam of this Example had a density (pcf.) of 61.43; atensile strength (p.s.i.) of 1940; a tensile modulus (p.s.i., 100%) of1800; an elongation (percent) of 115; a split tear (pounds per inch) of175; a Graves tear (Die C, pounds per inch) of 424; a Shore D hardnessof 53-51; a flex recovery of 14/8; a flex modulus (pounds per squareinch×10³) of 65.88, 30.99, and 14.54 at minus 20 degrees Fahrenheit, 72degrees Fahrenheit, and 150 degrees Fahrenheit, respectively; a heat sag(at 250 degrees Fahrenheit) of 0.13; and Dart impact ratings of NF, NF,and F at 20 degrees Fahrenheit, 10 degrees Fahrenheit, and 0 degreesFahrenheit, respectively.

Several of the properties of the polyurethane foam of Example 30 weresubstantially superior to the properties of the foam of Example 31. Itappears that the use of the carbamylbiuret-modified polyisocyanate ofthis invention improved the elongation, split tear, and Graves tearproperties.

COMPARATIVE EXAMPLE 32

In substantial accordance with the procedure of Example 30, apolyurethane foam was prepared using 100 parts of isocyanate 2; no otherisocyanate was used in this experiment.

The polyurethane foam of this Example had a density (pcf.) of 61.07; atensile strength (p.s.i.) of 1970; a tensile modulus (p.s.i., 100%) of1675; an elongation (percent) of 195; a split tear (pounds per inch) of344; a Graves tear (Die C, pounds per inch) of 508; a Shore D hardnessof 54-48; a flex recovery of 16/8; a flex modulus (pounds per squareinch×10³) of 107.11, 27.82, and 7.52 at 20 degrees Fahrenheit, 72degrees Fahrenheit, and 150 degrees Fahrenheit, respectively; a heat sag(at 250 degrees Fahrenheit) of 0.55; and Dart impact ratings of NF/F,NF/F, and F at 20 degrees Fahrenheit, 10 degrees Fahrenheit, and 0degrees Fahrenheit, respectively.

The elongation and split tear properites of the polyurethane foam ofExample 30 was substantially superior to the elongation and split tearproperties of the polyurethane foam of this Example.

EXAMPLES 33 and 34

In substantial accordance with the procedure of Example 30, apolyurethane foam was prepared from an isocyanate blend containing 75parts of isocyanate 3 and 25 parts of the isocyanate of Example 9.

In substantial accordance with the procedure of Example 30, apolyurethane foam was prepared from an isocyanate blend containing 75parts of isocyanate 3 and 25 parts of isocyanate 2.

The properties of each of these foams were determined; these propertiesare shown below.

    ______________________________________                                                       Foam Produced                                                                 from Blend                                                                              Foam Produced                                                       Containing                                                                              from Blend                                                          25 Parts of                                                                             Containing                                                          the Isocyanate                                                                          25 Parts of                                                         of Example 9                                                                            Isocyanate 2                                         ______________________________________                                        Density (pcf.)   63          61                                               Tensile strength (p.s.i.)                                                                      2280        2015                                             Tensile modulus (p.s.i., 100%)                                                                 1935        1860                                             Elongation (percent)                                                                           180         135                                              Split tear (p.i.)                                                                              225         171                                              Graves tear (Die C, p.i.)                                                                      439         412                                              Shore D hardness 54-52       54-56                                            Flex recovery    10/5        13/7                                             Heat sag @ 250° C.                                                                      0.21        0.12                                             Flex modulus (p.s.i. × 10.sup.3)                                        -20° F.   57.27       54.71                                            72° F.    27.1        25.6                                             150° F.   13.79       13.70                                            Dart impact at                                                                20° F.    NF          NF                                               10° F.    NF          NF                                               0° F.     F           F                                                ______________________________________                                    

It appears that the use of the carbamylbiuret-modified isocyanate ofthis invention improved the elongation, split tear, and Graves tearproperties of the polyurethane foam.

EXAMPLES 35 and 36

In substantial accordance with the procedure of Example 30, apolyurethane foam was prepared from an isocyanate blend containing 75parts of isocyanate 2 and 25 parts of the isocyanate of Example 10.

In substantial accordance with the procedure of Example 30, apolyurethane foam was prepared from an isocyanate blend containing 75parts of isocyanate 2 and 25 parts of isocyanate 3.

The properties of each of these foams were determined; these propertiesare shown below.

    ______________________________________                                                       Foam Produced                                                                 from Blend                                                                              Foam Produced                                                       Containing                                                                              from Blend                                                          25 Parts of                                                                             Containing                                                          the Isocyanate                                                                          25 Parts of                                                         of Example 10                                                                           Isocyanate 3                                         ______________________________________                                        Density (pcf.)   62          61                                               Tensile strength (p.s.i.)                                                                      2150        2155                                             Tensile modulus (p.s.i., 100%)                                                                 1805        1845                                             Elongation (percent)                                                                           245         185                                              Split tear (p.i.)                                                                              241         225                                              Graves tear (Die C, p.i.)                                                                      582         463                                              Shore D hardness 52-49       55-52                                            Flex recovery    15/8.5      12/8                                             Heat sag @ 250° C.                                                                      0.18        0.25                                             Flex modulus (p.s.i. × 10.sup.3)                                        -20° F.   72.74       79.67                                            72° F.    27.77       29.12                                            150° F.   13.43       13.43                                            Dart impact at                                                                20° F.    NF          NF                                               10° F.    NF/F        NF/F                                             0° F.     F           F                                                ______________________________________                                    

The use of the isocyanate of this invention substantially improved theelongation and Graves tear properties of the polyurethane foam.

EXAMPLES 37-41

In substantial accordance with the procedure of Example 30, polyurethanefoams were prepared from various isocyanate blends. In Example 37 theblend contained 50 parts of isocyanate 3 and 50 parts of the isocyanateof Example 3. In Example 38 the blend contained 75 parts of isocyanate 3and 25 parts of the isocyanate of Example 15. In Example 39 the blendcontained 50 parts of isocyanate 2 and 50 parts of the isocyanate ofExample 15. In Example 40 the blend contained 75 parts of isocyanate 3and 25 parts of the isocyanate of Example 16. In Example 41 the blendcontained 75 parts of isocyanate 2 and 25 parts of the isocyanate ofExample 16.

The properties of each of these foams were determined and are shownbelow.

    ______________________________________                                                  37    38      39      40     41                                     ______________________________________                                        Density (pcf)                                                                             63      63      66    63     61                                   Tensile strength                                                                          1950    2065    1733  2090   2120                                 (p.s.i.)                                                                      Tensile modulus,                                                                          1820    1855    1633  1850   1770                                 p.s.i., 100%                                                                  Elongation, Percent                                                                       115     155     183   145    265                                  Split tear, p.i.                                                                          130     211     307   212    475                                  Graves tear, Die C,                                                                       344     388     440   425    500                                  p.i.                                                                          Shore D hardness                                                                          50-43   53-52   57-51 54-51  56-52                                Flex recovery                                                                             9/5.5   12.58   18/11 11/6.5 16.8.5                               Heat sag @ 250° F.                                                                 0.25    0.20    0.43  0.18   0.28                                 Flex modulus,                                                                 p.s.i. × 10.sup.3                                                       -20° F.                                                                            41.36   61.93   84.59 56.56  76.66                                72° F.                                                                             17.89   27.77   28.68 26.58  28.0                                 150° F.                                                                            11.84   13.43   14.53 12.78  11.37                                Dart impact at                                                                20° F.                                                                             NF      NF      F     NF     NF                                   10° F.                                                                             NF      NF/F    --    NF     NF/F                                 0° F.                                                                              NF      F       F     F      F                                    ______________________________________                                    

When the procedure of Example 30 is repeated with the exception that adifferent isocyanate blend is used, similarly good results are obtained.Carbamylbiuret-modified polyisocyanates are prepared with the followingorganic diisocyanates and urea-type compunds in substantial accordancewith the procedure described in Examples 1-27. Each of the organicdiisocyanates selected from the group consisting of 4,4-dephenylmethanediisocyanate, p-phenylene diisocyanate, p-xylylene diisocyanate, and4,4'-biphenyl diisocyanate is reacted with each of the urea compoundsselected from the group consisting of N,N-diethylurea,N,N-di-i-propylurea, N,N-di-n-propylurea, N,N-dicyclohexylurea,5-ethylhydantoin, 5,5-diethylhydantoin, and 1,3-diphenylguanidine. Whenthese polyisocyanates are used to prepare microcellular polyurethanefoams, good results are obtained.

The carbamylbiuret-modified polyisocyanate of this invention is morelinear and symmetrical than prior art products; and it can be used toprepare elastomeric products with physical properties which are superiorto prior art elastomers. These novel carbamylbiuret-modifiedpolyisocyanates are capable of forming hydrogen bonds; it is believedthat, for elastomer applications, this capability enables these novelpolyisocyanates to form hydrogen bonds and to increase strengthproperties and ring-pseudo-ring packing of the type which willconstitute a hard phase, thereby improving the properties of theelastomer.

EXAMPLES 42-46

The specified amounts of isocyanate 3 and a urea-type compound wereheated under the time and temperature conditions described until the NCOcontent reached a predetermined level. In Examples 42, 43, and 44 theurea-type compound was 1,3-dimethylurea; in Examples 45 and 46 theurea-type compound was 5,5-dimethylhydantoin.

    __________________________________________________________________________                Parts of                                                               Parts of                                                                             Urea-Type                                                                           Reaction                                                                             Reaction                                                  Isocyanate 3                                                                         Compound                                                                            Temperature,                                                                         Time,     Viscosity                                  Example                                                                            (by weight)                                                                          (by weight)                                                                         °C.                                                                           hours                                                                              % NCO                                                                              CPS/°C.                             __________________________________________________________________________    42   100    3     100    0.5  26.1 100/26                                     43   100    6     100    7.5  23.7 380/28                                     44   100    4      80    0.5  25.5 141/27                                     45   100    3     100    5.0  26.6 150/26                                     46   100    3     200    1.0  25.7 450/26                                     __________________________________________________________________________

EXAMPLES 47-52

In substantial accordance with the procedure described for Examples42-46, an isocyanate blend containing 50 parts (by weight) of isocyanate3 and 50 parts (by weight) of isocyanate 1 were heated with thespecified amounts of a urea-type compound under the time and temperatureconditions described until the NCO content reached a predeterminedlevel. In Examples 47, 48 and 49 the urea-type compound was1,3-dimethylurea; in Examples 50, 51 and 52 the urea-type compound was5,5-dimethylhydantoin.

    ______________________________________                                              Parts of                                                                      Urea-Type Reaction   Reaction                                           Ex-   Compound  Temperature,                                                                             Time,  %     Viscosity                             ample (by weight)                                                                             °C. hours  NCO   CPS/°C.                        ______________________________________                                        47    1.5       100        1.0    29.5  55/26                                 48    2.0       100        0.5    28.9  34/53                                 49    3.0       100        0.25   28.2  39/53                                 50    1.5       200        1.0    28.9  40/53                                 51    2.0       200        1.0    29.0  37/67                                 52    3.0       200        0.5    28.5  40/69                                 ______________________________________                                    

EXAMPLES 53-54

In substantial accordance with the procedure described for Examples42-46 an isocyanate blend containing 300 grams of isocyanate 1 and 300grams of isocyanate 3 was reacted with either 36 grams of diethyl urea(Example 53) or 36 grams of dicyclohexyl urea (Example 54).

In the experiment of Example 53, the reaction mixture was heated at 100degrees Centigrade for 2.0 hours until the NCO content of the reactionmixture was 27.0 percent; a product with a viscosity (at 25 degreesCentigrade) of 66 centipoises was obtained. In the experiment of Example54, the reaction mixture was heated at 120 degrees Centigrade for 4.0hours until the NCO content of the reaction mixture was 27.7 percent; aproduct with a viscosity (at 25 degrees Centigrade) of 70 centipoiseswas obtained.

EXAMPLE 55

A resin blend was prepared by mixing 200 parts (by weight) of polyol 2,4.0 parts (by weight) of a catalyst solution consisting of a 1:3 (byweight) mixture of triethylene diamine and 1,4-butanediol, 40 parts (byweight) of 1,4-butanediol, and 0.04 parts (by weight) ofdibutyltindilaurate. One hundred forty-four point six (144.6) parts (byweight) of the isocyanate of Example 42 and 200 parts of the resin blendwere charged into a quart Plastikan and agitated with a high-speed drillfitted with a Cowles dissolver for 10 seconds. The system blend waspoured quickly into an all-aluminum mold preheated to a temperature of130-140 degrees Fahrenheit. After four minutes, the resulting solid padwas pulled from the mold and post-cured in an oven for one hour at atemperature of 250 degrees Fahrenheit. The solid pad was then aged forfrom about 3 to about 5 days at room temperature and thereafterevaluated.

The polyurethane foam of this Example had a density (pcf.) of 55.2; atensile strength (p.s.i.) of 1720; an elongation (percent) of 120; asplit tear (pounds per inch) of 115; a Graves tear (pound per inch) of323; a Shore D hardness (Inst./5 seconds) of 47/43; a heat sag (at 250degrees Fahrenheit) of 0.34; a flexural recovery of 15/9; and flexuralmoduli (in thousands of pounds per square inch) of 43.17, 16.88, and7.86 at minus 20 degrees Fahrenheit, 72 degrees Fahrenheit, and 150degrees Fahrenheit, respectively.

EXAMPLES 56-97

In substantial accordance with the procedure described in Example 55,polyurethane foams prepared from the isocyanate of this invention wereproduced. A resin blend was prepared by mixing 100 parts (by weight) ofa polyol, 2.0 parts (by weight) of a catalyst solution consisting of a1:3 (by weight) mixture of triethylene diamine and 1,4-butanediol,1,4-butanediol, and 0.02 parts (by weight) of dibutyltindilaurate. InExamples 56-65 and 77-87, 20 parts (by weight) of 1,4-butanediol wereused; in Examples 66-76 and 88-97, 25 parts (by weight) of1,4-butanediol were used. Polyol 2 was used in Examples 56-76; a 4000molecular weight diol (polyol 3) was used in Examples 77-97. Theisocyanates used in these experiments are described below.

    ______________________________________                                                 Example Which                                                                 Describes the                                                                 Preparation of                                                                the Isocyanate                                                                Used in this  Amount of Isocyanate                                   Example  Example       Used (parts by weight)                                 ______________________________________                                        56       43            79.6                                                   57       44            74.0                                                   58       47            63.9                                                   59       48            65.3                                                   60       49            66.9                                                   61       45            70.9                                                   62       46            73.4                                                   63       50            65.3                                                   64       51            65.1                                                   65       52            66.2                                                   66       42            84.3                                                   67       43            92.8                                                   68       44            86.4                                                   69       47            74.6                                                   70       48            76.1                                                   71       49            77.9                                                   72       45            84.6                                                   73       46            85.6                                                   74       50            76.1                                                   75       51            75.8                                                   76       52            77.2                                                   77       42            72.6                                                   78       43            79.6                                                   79       44            74.4                                                   80       47            64.2                                                   81       48            65.6                                                   82       49            67.2                                                   83       45            71.3                                                   84       46            73.7                                                   85       50            65.6                                                   86       51            65.3                                                   87       52            66.4                                                   88       43            93.1                                                   89       44            86.6                                                   90       47            74.8                                                   91       48            76.3                                                   92       49            78.2                                                   93       45            84.7                                                   94       46            85.8                                                   95       50            76.3                                                   96       51            76.0                                                   97       52            77.4                                                   ______________________________________                                    

The properties of the polyurethane foams of these examples are shown inTable I.

                                      TABLE I                                     __________________________________________________________________________              Tensile  Split                                                                            Graves                                                                            Shore D                                                                            Heat   Flexural Modulus,                       Density   Strength                                                                           Elong.                                                                            Tear                                                                             Tear                                                                              Inst./                                                                             Sag @                                                                             Flex                                                                             p.s.i. × 10.sup.3                 Example                                                                            pcf. p.s.i.                                                                             %   p.i.                                                                             p.i.                                                                              5 sec.                                                                             250° F.                                                                    Rec.                                                                             -20° F.                                                                     72° F.                                                                     150° F.                 __________________________________________________________________________    56   54   1570 200 221                                                                              305 49/44                                                                              0.08                                                                              22/15                                                                            50.10                                                                              20.32                                                                             8.43                           57   46   1300 180 150                                                                              233 48/39                                                                              0.42                                                                              20/13                                                                            45.47                                                                              15.85                                                                             6.22                           58   61   2000 150 113                                                                              413 50/48                                                                              0.2 11/8                                                                             35.48                                                                              15.56                                                                             10.44                          59   61   2010 140 123                                                                              378 48/42                                                                              0.16                                                                              10/7                                                                             37.53                                                                              17.30                                                                             11.32                          60   61   1760 100 153                                                                              380 52/44                                                                              0.18                                                                              11/8                                                                             36.71                                                                              16.55                                                                             11.71                          61   62   2040 140 143                                                                              360 52/49                                                                              0.38                                                                               9/5                                                                             53.68                                                                              18.17                                                                             9.58                           62   62   1700 120 112                                                                              283 49/44                                                                              0.34                                                                               8/4                                                                             25.62                                                                              10.30                                                                             5.69                           63   62   2020 140 143                                                                              356 51/44                                                                              0.20                                                                              10/7                                                                             35.83                                                                              23.24                                                                             10.71                          64   65   1530 60  144                                                                              395 48/44                                                                              0.16                                                                              10/7                                                                             41.96                                                                              17.8                                                                              11.40                          65   59   1790 100 128                                                                              379 48/44                                                                              0.16                                                                              11/6                                                                             42.35                                                                              16.73                                                                             11.55                          66   57   2100 140 167                                                                              393 53/51                                                                              0.80                                                                              20/14                                                                            82.0 35.16                                                                             17.48                          67   57   1900 140 216                                                                              431 56/52                                                                              0.88                                                                              74/15                                                                            85.21                                                                              37.00                                                                             19.13                          68   57   1920 130 214                                                                              413 54/51                                                                              0.30                                                                              23/16                                                                            75.63                                                                              33.91                                                                             15.09                          69   62   2400 120 153                                                                              429 53/47                                                                              0.28                                                                              12/8                                                                             57.90                                                                              28.04                                                                             17.79                          70   66   2250 110 186                                                                              403 54/44                                                                              0.18                                                                              10/6                                                                             54.80                                                                              26.00                                                                             17.74                          71   60   2180 80  176                                                                              401 46/43                                                                              0.20                                                                              13/8                                                                             53.91                                                                              27.05                                                                             19.64                          72   52   1700 70  105                                                                              271 50/45                                                                              0.16                                                                              11/6                                                                             51.14                                                                              22.64                                                                             13.70                          73   53   1970 100 120                                                                              298 51/44                                                                              0.20                                                                              16/10                                                                            52.80                                                                              21.59                                                                             11.96                          74   62   2500 120 179                                                                              434 49/46                                                                              0.16                                                                              10/5                                                                             60.87                                                                              28.11                                                                             18.08                          75   63   2400 110 168                                                                              529 53/48                                                                              0.20                                                                              10/5                                                                             64.35                                                                              29.91                                                                             18.78                          76   62   2450 120 190                                                                              481 52/47                                                                              0.14                                                                              11/7                                                                             67.61                                                                              28.52                                                                             18.37                          77   57   1520 200 211                                                                              338 48/43                                                                              0.76                                                                              12/7                                                                             50.40                                                                              16.52                                                                             6.65                           78   54   1300 150 137                                                                              275 47/41                                                                              1.36                                                                              16/10                                                                            48.54                                                                              15.43                                                                             5.53                           79   60   1320 100 168                                                                              356 54/42                                                                              0.34                                                                              19/11                                                                            73.04                                                                              27.69                                                                             8.24                           80   65   1810 190 373                                                                              476 47/36                                                                              0.28                                                                               8/5                                                                             32.77                                                                              14.01                                                                             8.74                           81   65   1700 150 225                                                                              395 43/32                                                                              0.34                                                                               6/5                                                                             30.59                                                                              11.48                                                                             7.54                           82   64   1180 80  208                                                                              306 41/29                                                                              0.50                                                                               8/4                                                                             23.64                                                                              7.69                                                                              5.15                           83   55   1500 140 136                                                                              298 48/43                                                                              0.52                                                                              13/8                                                                             44.48                                                                              15.94                                                                             7.65                           84   59   1180 60  120                                                                              255 44/34                                                                              0.44                                                                              10/5                                                                             29.26                                                                              10.64                                                                             6.78                           85   63   1990 200 188                                                                              460 49/38                                                                              0.26                                                                               6/3                                                                             36.30                                                                              14.19                                                                             9.11                           86   64   2080 210 229                                                                              480 41/32                                                                              0.32                                                                               5/2                                                                             33.04                                                                              13.60                                                                             9.11                           87   66   2100 220 279                                                                              529 48/44                                                                              0.46                                                                               7/3                                                                             39.86                                                                              14.89                                                                             9.32                           88   58   1530 70  212                                                                              393 56/51                                                                              0.64                                                                              29/19                                                                            104.01                                                                             35.36                                                                             12.23                          89   57   1590 160 260                                                                              418 54/52                                                                              0.70                                                                              18/10                                                                            90.39                                                                              30.59                                                                             11.90                          90   63   2050 130 281                                                                              495 53/45                                                                              0.26                                                                              11/5                                                                             52.44                                                                              21.01                                                                             12.64                          91   65   2250 150 233                                                                              516 54/49                                                                              0.26                                                                              10/6                                                                             53.91                                                                              23.20                                                                             14.86                          92   60   1690 80  243                                                                              416 53/45                                                                              0.22                                                                              11/6                                                                             53.62                                                                              20.55                                                                             12.05                          93   54   2000 120 137                                                                              354 52/48                                                                              0.26                                                                              12/6                                                                             59.25                                                                              25.94                                                                             13.73                          94   54   1800 130 118                                                                              299 50/42                                                                              0.1 10/5                                                                             43.4 15.7                                                                              8.7                            95   64   2300 170 288                                                                              555 53/45                                                                              0.16                                                                               9/5                                                                             64.84                                                                              25.44                                                                             14.38                          96   65   2290 160 296                                                                              500 54/49                                                                              0.22                                                                               7/3                                                                             63.36                                                                              25.84                                                                             15.87                          97   62   2110 170 315                                                                              563 43/45                                                                              0.24                                                                              10/5                                                                             66.65                                                                              24.60                                                                             14.50                          __________________________________________________________________________

COMPARATIVE EXAMPLES 98-101

In substantial accordance with the procedure described in Example 55,polyurethane foams derived from isocyanate 3 were prepared. In each ofthese Examples, the specified amounts of isocyanate 3 were reacted witha resin blend prepared from 100 parts (by weight) of polyol,1,4-butanediol, 2.0 parts (by weight) of a catalyst solution consistingof a 1:3 (by weight) mixture of triethylene diamine and 1,4-butanediol,and 0.02 parts (by weight) of dibutyltindilaurate. In Examples 98 and100, 20 parts (by weight) of 1,4-butanediol were used; in Examples 99and 101, 25 parts (by weight) of 1,4-butanediol were used. Sixty-threepoint four (63.4), 78.4, 77.8, and 78.6 parts of isocyanate 3 were usedin Examples 98, 99, 100, and 101, respectively. Polyol 2 was used inExamples 98 and 99; polyol 3 was used in Examples 100 and 101.

The properties of the polyurethane foams of these experiments aredescribed below.

    ______________________________________                                                   98     99       100      101                                       ______________________________________                                        Density, pcf.                                                                              68       64       64     63                                      Tensile strength, p.s.i.                                                                   2270     2380     2170   2480                                    Elongation, percent                                                                        70       50       110    70                                      Split tear, p.i.                                                                           79       100      130    140                                     Graves tear, p.i.                                                                          312      394      400    441                                     Shore D hardness,                                                                          54/59    60/52    57/47  58/53                                   Inst./5 sec.                                                                  Heat sag at 250° F.                                                                 0.68     0.54     0.34   0.36                                    Flex recovery                                                                              12/9     16/11    12/9   14/9                                    Flex modulus,                                                                 p.s.i. × 10.sup.3                                                       -20° F.                                                                             49.42    71.53    51.90  96.09                                   72° F.                                                                              22.34    35.30    23.41  34.47                                   150° F.                                                                             15.29    22.65    15.27  23.10                                   ______________________________________                                    

The use of the isocyanate of this invention in the polyurethane foams ofExamples 45-65 improved the tear strength, heat sag, and flexuralmodulus properties of the foam; compare the properties of these foamswith those of the foam of Example 98. The use of said isocyanate in thefoams of Examples 66-76 improved their elongation, tear strength, heatsag, and flexural modulus properties. The polyurethane foams of Examples77-87 and 88-97 demonstrate improved elongation and tear strengthproperties.

Although the invention has been described in considerable detail in thisspecification, it is to be understood that such detail is solely for thepurpose of illustration and that many variations may be made by thoseskilled in the art without departing from the spirit and scope of theinvention.

The embodiments of this invention in which an exclusive privilege orproperty is claimed are as follows:
 1. A carbamylbiuret-modifiedpolyisocyanate of the formula: ##STR11## wherein n is an integer of fromabout 1 to about 20; R is a divalent hydrocarbon radical containing fromabout 1 to about 18 carbon atoms; and Y is the divalent radical selectedfrom the group consisting of ##STR12## wherein X, X', and X" areindependently selected from the group consisting of oxygen and sulfur;R⁴, R⁵, R⁶, and R⁷ are independently selected from the group consistingof hydrogen, alkyl containing from about 1 to about 6 carbon atoms,cycloalkyl containing from about 3 to about 7 carbon atoms, phenyl, andbenzyl.
 2. The carbamylbiuret-modified polyisocyanate of claim 1,wherein R is an aromatic divalent radical containing from about 6 toabout 15 carbon atoms.
 3. The carbamylbiuret-modified polyisocyanate ofclaim 2, wherein X, X' and X" are oxygen.
 4. The carbamylbiuret-modifiedpolyisocyanate of claim 3, wherein said R is ##STR13## and R⁸ is methyland a and b are integers of from 0 to
 2. 5. The carbamylbiuret-modifiedpolyisocyanate of claim 4, wherein said R is ##STR14##
 6. Acarbamylbiuret-modified polyisocyanate of the formula: ##STR15## whereinn is an integer of from about 1 to about 20; R is a divalent hydrocarbonradical containing from about 1 to about 18 carbon atoms; and Y is thedivalent radical selected from the group consisting of ##STR16## whereinX, X', and X" are independently selected from the group consisting ofoxygen and sulfur; R⁴, R⁵, R⁶, and R⁷ are independently selected fromthe group consisting of hydrogen, alkyl containing from about 1 to about6 carbon atoms, cycloalkyl containing from about 3 to about 7 carbonatoms, phenyl, and benzyl wherein said polyisocyanate contains fromabout 2 to about 50 percent by weight of the polyisocyanate ofcarbodiimide-containing species.
 7. The polyisocyanate of claim 6,wherein R is an aromatic divalent radical containing from about 6 toabout 15 carbon atoms.